This project seeks to make three important contributions to the history of tuberculosis in the United States during the late nineteenth and early twentieth centuries. First, it examines tuberculosis in a major metropolitan area, which has received little attention from medical historians. Although several historians have shown how the medical, social, and cultural context of tuberculosis changed over time, most restrict their purview to the East Coast. The disease had a very different meaning in a region that promoted itself as uniquely healthy. Second, the project broadens the understanding of the relationship between tuberculosis and immigrant groups. The association with tuberculosis had an even more devastating impact on Mexicans in Los Angeles than on the European immigrants in the East Coast, whom medical historians previously have examined. Reports of high rates of tuberculosis among Mexicans hardened the perception that they were "illegal aliens" and contributed not only to the campaign to restrict their immigration in the 1920s but also to their expulsion in the 1930s. Third, the study focuses on tuberculosis as a communicable as well as a chronic disease. Recent historical studies have demonstrated how the discovery of the tubercle bacillus and gradual acceptance of the germ theory transformed the medical treatment, social situation, and cultural representation of people with tuberculosis during the late nineteenth and early twentieth centuries. Major changes in the understanding of disability also profoundly affected tubercular people. This project thus seeks to apply some of the insights of the new disability history to the study of tuberculosis. This historical study relies primarily on in-depth analysis of extensive archival sources.